Mill



Nov. 6, 1928. 1,690,494

F. E. MARcY v MILL Original Filed June 7, 1927 Q; XINVENTQR v PatentedNov. 6,

UNITED STATES PATENT, OFFICE.

FRANK E. MARCY, OF SAN DIEGO, CALIFORNIA.

MILL.

Original application filed June 7, 1927, Serial No. 197,054. Divided andthis application filed December 28,

1927. Serial No. 243 051.

This invention relates to an improvement in reducing mills in which thematerial to be reduced is confined within a rotary drum or barreltogether with the reducing medium which may be inthe form of balls,pebbles, cubes, rods, etc., the material being crushed or reduced byimpact and attrition as the mill load tumbles andcascades due torotation of the mill drum.

One of the objects of my invention is the provision of a mill of thetype above indicated, in which the oversize of the load is worked awayfrom the grate to effect increased efiiciency of operation.

In mills of the type to which this invention "is directed, there is aconstant migration of the mill load toward the discharge end, due to thecontinuous feeding of material to the drum and the constant discharge ofmaterial from the discharge end of the mill, and the present inventionprovides for increasing this migrating action and for movement of theoversize of the load in the opposite direction, i. e., toward the feedend, this not only resulting in a more circuitous travel of the millload but effecting a marked increase in the discharge of fines from themill, in that the grate is thereby maintained relatively free ofoversize and reducing medium to permit of the ready escape of the finesthrough the grate openings.

It will be seen, therefore, that the present mill is of such a characterthat migration of the entire load toward the discharge end is expeditedwhile means are provided for moving the reducing medium and oversizeaway from the grate, thereby to reduce plugging or blocking of the grateopenings by the over size and reducing medium, permitting the fines toescape fromthe mill through the grate openings and increasing therebythe eiticiency of the mill.

In the drawing accompanying this application, an embodiment of myinvention is shown in sectional elevation, the drawing being somewhatdiagrammatic.

The drum 1 is'provided on its interior with liners 6, these liners, asillustrated, being so constructed and arranged as to slope toward thedischarge head 3 at the ascending side of the mill drum, it beingassumed that the drum is rotating toward the observer, as viewed in thedrawing. Adjacent the dis charge end of the mill I provide grate sectors7 disposed about a substantially conical memher 8, the grate sectorsabutting this conical member andbeing held in place-by clamp bars 9,together with end clamp bars 10 which are set up from the exterior ofthe mill by bolts 11. The grate sectors, as will be seen from thedrawing, are inclined outwardly relatively to the longitudinal axis oraxis of rotation of the mill drum and provides a frusto-conicalstructure the base of which faces the discharge end of the mill. Theconical member 8 is centrally disposed with respect to the grate and theinner face of this conical member projects inwardly a short distancebeyond the inner face of the. grate or grate sectors 7 As stated at theoutset, the present invention has for one of its objects, the provisionof a mill structure in which migration of the mill load toward the grateis expedited,

These objects of the liners toward the grates on the ascending side ofthe mill drum. The action of the grates 7 in the rotation of the mill isto screen the material which has been brought to the face of thesegrates due to the rotation of the mill drum and the action'of the liners6, so that the fines will be discharged through the grates and fromthence will find their way through the discharge trunnion 5 to theexterior of the mill. The grates, however, due to their inclination andtheir cooperation with the conical member 8 will cause the oversizewhich is not sufliciently reduced to escape through the grates 7 to fallupon the conical member 8 to be deflected thereby toward the feed. endof the mill for further reduction. In operation, therefore, it will beapparent the grates 7, in conjunction with the conical member 8, willclear themselves of oversize and reducing mediumto permit of the rapiddischarge of fines therethrough which otherwise would be prevented fromescaping from the mill due to the grate openings being blocked orplugged by this oversize materialQ The net result of this constructionis to increase the movement of the mill load toward the grates and towork the oversize material away from the grates thereby enabling anincreased amount of material to be reduced and to be discharged from themill in a given length of time as compared with structures employed inthis art heretofore. This application is a division of my co-pendingapplication Serial No. 197,054, filed June 7, 1927.

What I claim is:

l. A mill comprising a rotary drum or barrel,'inclined grate membersadjacent the discharge end, and a member cooperating with said grates tofree the grate members of oversize.

2. A mill comprising a rotary drum or barrel, inclined grate membersadjacent the discharge end of the drum, and a member about which thegrate members areassembled and with which the grate members cooperate tofree the grate members of oversize. H

3. A mill comprising a rotary drum or barrel having a feed head and adischarge head, inclined grate sectors at the discharge end of the mill,and a conical member about which said inclined grate sectors areassembled and with which the grate sectors cooperate to free the grateof oversize.

4. A mill comprising a rotary drum or barrel, grates at the dischargeend arranged to provide a frusto-conieal structure, and a substantiallyconical member centrally disposed with respect to said grate andcooperating therewith to free the grate of oversize.

5. A mill comprising a rotary drum or barrel, grates at the dischargeend providing a frusto-cone having its base facing the discharge end ofthe mill, a substantially conical member centrally disposed with respectto said grate and cooperating therewith to free the grate of oversize.

6. A mill comprising a rotary drum or barrel, grate sectors adjacent thedischarge end, said grate sectors being so disposed as to provide afrusto-conical structure having its base facing the discharge end of themill, and a substantially conical member positioned centrallyof thegrate structure about which the grate sectors are assembled and withwhich they cooperate to be freed ofoversize.

7. A mill comprising a rotary drum or barrel, grate sectors within thedrum, said grate sectors being inclined with respect to the axis ofrotation of the drum to provide a frustoconical structure having itsbase facing the mill load is migrated by said liners, saidgrateproviding a frusto-conical structure having its base facing thedischarge end of the mill drum, a substantially conical member centrallydisposed with respect to the grate structure, said liners, gratestructure and centrally disposed member cooperating to effect anincrease in the movement of the mill load toward the grate and adecrease in accumulation of oversize adjacent the face of the grate.

9. A mill comprising a rotary drum or barrel, liners therefor slopingtoward the discharge end of the drum on the ascending side thereof, andan inclined grate structure adjacent the discharge end of the mill drumand cooperating with the sloping liners, to expedite the discharge offines through the grate.

10. A mill comprising a rotary drum or barrel, liners therefor slopingtoward the discharge end of the mill on the ascending side of themilldrum, a grate structure adjacent the discharge end of the mill andinclined outwardly of the mill drum toward the discharge end of themill, a substantially conical member disposed centrally of the grate andcooperating with the inclined liners and grate, to expedite thedischarge of fines through the grate and to reduce the accumulation ofoversize at the grate.

11. A mill comprising in combination a rotary drum or barrel, linerstherefor, said liners sloping toward the discharge end of the mill onthe ascending side of the drum, and providing a formation for migratingthe mill load toward the discharge end of the drum, a discharge head forsaid drum, grate sectors adjacent, said head-, a eonieal member disposedin the axis of rotation of t-lic mill drum and about which said gratesectors are assembled, means for securing said conical member in place,means for clamping the grate sectors in place about said conical memberto provide a substantially frusto-conical grate structure the base ofwhich faces the discharge end of the mill drum, said liners, gratesectors and conical member cooperating to expedite movement of the millload toward the grate and to reduce the accumulation of oversize at thegrate.

This specification signed this 19th day of December, 1927.

FRANK E. MARCY.

